Hi; in Safari only, we noticed that there appears to be a significant pixel-shift that occurs, shifting the entire interactivity, when we embed hotspots in an IFRAME. Some of our users have commented on the effect. Outside of an iframe, in the authoring environment on H5P.COM, and in other browsers, the shift does not occur.

I made a short video demonstrating the effect in Safari on the H5P.ORG example page:

Hi; I checked, and it seems to appear whether or not I'm in full-screen mode. I have Safari open, and it's maximized but not full-screen (i.e. not View> Enter Full Screen), but in either case, the effect is there. I'm on High Sierra, 10.13.6, but my other colleagues also notice the effect as well.